Tamoxifen(1-p-.beta.-dimethylaminoethoxyphenyl-trans-1,2-diphenylbut-1-ene) , represented by the structure ##STR2## is a well known antiestrogenic compound which is useful for the treatment and prevention of mammalian breast carcinoma. See, The Merk Index, 11th Ed., 1430 (1989). Although tamoxifen is quite efficacious in the treatment/prevention of this disease, it is known to induce certain uterotrophic effects which can be detrimental to the tamoxifen patient. It, therefore, would be beneficial if a pharmaceutical agent was available which would not affect the antineoplastic benefit which tamoxifen provides while minimizing or eliminating its detrimental uterotrophic effect.
Thus, the present invention provides a method of minimizing the uterotrophic effect of tamoxifen and certain tamoxifen analogs via the concurrent or sequential administration of certain known nuclear regulating benzothiophene pharmaceutical agents. Also provided are pharmaceutical compositions.